Sports footwear

Abstract: Improved sports footwear comprising an insert positioned at least in the heel region, the insert comprising an elastically deformable cellular structure arranged within an elastically deformable air-impermeable casing provided with inner projections on opposing faces, the casing being pneumatically connected to controllable means, rigid with the footwear, for varying the air pressure within the casing so as to modify the elastic characteristics of the insert, each projection on one face being connected to a projection on the other face.

Description: This invention relates to improved footwear for athletes, of the type containing an insert at least in the heel region of the sole, the insert comprising a airtight flexible plastics casing enclosing elastically deformable means. An example of this type of footwear is disclosed in US-A 5.092.060. It is well known that athletics footwear must provide a stable support region which at the same time is comfortable for the foot and hence for the athlete's body, which is subjected to the most various types of stress. To solve the problem of comfort with stable support, while also achieving a certain counter thrust effect, ie a partial recovery of the thrust as the footwear separates from the ground plus absorption of the impact against the ground, solutions of the type described in the preceding paragraph have been proposed. The known-art inserts (see e.g. US-A 5.092.060) positioned in the footwear heel of the sole act primarily as a comply spring, so that after the impact of the footwear against the ground and the simultaneous damping affect, there is partial restitution of the energy absorbed by the insert on impact. Although the known inserts offer comfort, stability and adequate damping ad energy recovery through a certain range of loading and impact velocity, they can prove partially unsatisfactory outside these rages. For example, footwear provided with the insert in question can satisfy the requirements of slow movement but not of fast movement, whereas an insert designed for fast movement could prove too rigid for slow movement. In addition to this, for equal footwear see the weight of the wearer can vary within extremely wide limits, so that the same insert can prove either excessively rigid or excessively yielding. The main object of the present invention is therefore to improve footwear provided with an insert of the type comprising an airtight casing of flexible material enclosing a plurality of interconnected elastic bodies, such that its rigidity can be matched both to the weight of the user and to the pace of movement at any given time. A further object of the present invention is to provide footwear with a airtight insert of reduced weight. A further object of the present invention is to provide footwear with several inserts positioned in regions of the footwear which are convenient for comfort and stability. The aforesaid objects are attained according to the invention by the inprovements recited in the attached claims. Document US-A 4.462.171 discloses a footwear having a compartmentalized, variable cushioning sole construction. The compartments are fluid-tight and independently inflatable through corresponding inlet valve means and include elastically deformable members. Neither inserts nor self-contained pumping and bleeding means are provided. Document EP-A1-0155.908 relates to a ski-boot having a substantially rigid outer shell and a padded inner shoe. Between shell and inner shoe there are provided air-cushions inflatable by pumping means carried by the outer shell so to fill the voids or cavities between shell and inner shoe. A bleed means is also provided. The purprose of this known solution is that of comfortably blocking the user's foot to the shell in order that a better control of the ski is achieved. The problem of rendering specific sole inserts more or less rigid is not tackled by the document. The invention will be more apparent from the detailed description of a preferred ambodiment thereof given hereinafter by way of nonlimiting example with reference to the accompanying drawing, in which: Figure 1 is a side view of the improved footware according to the invention; Figure 2 is an exploded perspective view of the insert; Figure 2A is a perspective view of the sole; Figure 3 is a partial section on the line A-A of Figure 2A with the cover for the pump and bleed valve omitted; Figure 4 shows to a different scale the sectional view of Figure 3, completed with the partial sectional view taken along line K-K of fig. 2 and comprising the cover; Figure 5 is a schematic view of the pneumatic circuit of the footwear. In the figures the reference numeral 1 indicates overall the sports footwear, which comprises a vamp 2 and a sole 3. The sole can also consist of one or more layers of plastic materials, which can be different. In the sole in a position corresponding with the user's heel there is provided a compartment containing an insert 4 formed from an elastically deformable cellular structure 5 of thermoplastics material enclosed in an airtight casing 6 of relatively thin flexible plastics material such as polyurethane or the like. Specifically, although non-limitatively, the cellular structure 5 defines a plurality of hexagonal cells 5A, some of which can be closed but only at one end, such as the cell 5A1. The cellular structure is prepared by moulding any elastic synthetic material and is free within the casing 6, ie not connected thereto. The casing 6 is formed from two parts 6A and 6B welded together, and prepared for example by vacuum-forming. The part 6A has a tray configuration with a perimetral flange 7 and an appendix 8 on one side, this appendix being centrally of semicircular shape (8A), and with two flat lateral flanges 8B. The tray part 6A also comprises an ordered series of substantially frusto-conical hollow projections 9 which extend within the interior of the casing obtained. The part 6B also comprises an appendix 10, which is substantially flat and is arranged to coincide with the appendix 8, and a series of frusto-conical hollow projections arranged to coincide with the projections 9 when the two parts 6A and 6B are joined together by welding along the superposed regions coinciding with the flanges 7 and 8B and with the inner ends 12 (see Figure 4). Before fixing the parts 6A, 6B of the casing 6 together, the light elastic cellular structure 5 is placed on one of these parts so that each of the hollow projections 9, 11 is located within a cell 5A (but obviously not within a cell 5A1, at which the parts 6A, 6B are without projections 9, 11). The other part of the casing 6 is then placed thereon and the parts joined together by welding along the said superposed regions to enclose the cellular structure 5 but without it being connected to the casing. The height of the cellular structure 5 is substantially equal to the inner distance between the opposing walls 13, 14 of the casing 6, but such that all the internal regions of the casing are connected together pneumatically. By the joining together of the appendices 8 and 10 a duct or tube Z is formed communicating with the interior of the casing. A cavity 15 and a channel 16 are provided in the sole 3. The cavity is provided in the heel and contains the insert 4 of corresponding shape, whereas the tube Z is positioned in the channel 16, which directs it to an outer lateral appendix 114 on the sole, where it terminates in an aperture in which it is fixed by a tubular appendix 115 of a plastics block 116 welded to the outside of the appendix 114 and comprising a chamber 17 in which the valving member 18 of a bleed valve 19 is slidingly mounted. The valving member 18 is of frusto-conical shape and is mounted at the end of a stem 20 of smaller cross-section. The stem passes slackly through a hole 21 and has a head 23. A compression spring 22 positioned between the block 16 and head 23 prevents the chamber 17 and hence the interior of the insert 4 being connected to atmosphere, whereas if the head 23 is pressed to hence withdraw the valving member 18 front the hole 21, the interior of the insert becomes connected to atmosphere via the space between the stem 20 and the hole 21 which guides it. The block 116 comprises a hollow lateral appendix 24 in which there is inserted a unidirectional valve 25 of elastic material comprising a seal flange 26, a tubular part 27 and two flat lips 28 which diverge to allow air to pass in the direction of the arrow R when pressure is applied to a bellows 29 of elastic material which by means of a lateral hollow appendix 30 is sealedly connected to the appendix 24. For this purpose the appendix 30 comprises an inner flange 31 which seats in a corresponding annular groove in the appendix 24 of the block 16. The bellows has a flat wall 29A by which it is fixed (welded) to the outer lateral appendix 114 of the sole. The bellows 29 comprises a second tubular appendix 35, opposite the preceding, in which there is mounted an intake valve 26 comprising a tubular member 37 with a groove 38 into which an inner flange of the appendix 35 elastically clamps. The tubular member 37 comprises a narrow passage 39 which can be intercepted by a plastics disc 40 which moves between this passage and a series of radially arranged spaced-apart teeth 41 which prevent the disc 40 from falling. As shown in Figure 4, a flexible cover 45 of elastomer material provided with a peripheral flange 46 is welded to the appendix 114 of the sole to cover and protect both the bellows pump 29 and the bleed valve 19. A hole 50 is provided in this cover for the necessary air movements. As Figure 4 represents a section on the line A-A of Figure 2A (completed by a section taken along line K-K of fig. 2) the reference numerals 55 indicate sections through walls common to two adjacent cells 5A, these walls lying in the sectional plane. In Figure 2 these walls are indicated by the same reference numerals 55. When the person wearing the footwear wishes to stiffen the insert 4, he presses repeatedly on the bellows 29. During this pressing, the air contained in the bellows is transferred into the insert 4, so stiffening it, via the delivery valve 25 (the intake valve 36 obviously being closed). When the user releases the bellows this returns to its initial position by virtue of its elasticity, to draw air into its interior via the intake valve 36 (the delivery valve remaining closed). On achieving the required rigidity the user ceases the pumping action. If he wishes to reduce the rigidity the user discharges pressure from the insert by pressing the head 23 of the bleed valve 19, to connect the insert 4 to atmosphere. As can be seen from Figure 2A, the footwear can also comprise a second insert 200 formed as the insert 4 and positioned in a seat 201 provided in the front part of the sole 3. A tube 202 similar to the tube Z pneumatically connects the insert 200 to the tube Z, allowing the rigidity of this second insert to also be simultaneously modified. This is achieved in the following manner: a) the part 14 and the corresponding part of the insert 200 are constructed in a single piece together with the appendix 10, which joins them together and comprises a lateral branch for connection to the block 116; b) the part 13 and the corresponding part of the insert 200 are constructed in a single piece together with the appendix 8, which joins them together and comprises a lateral branch to be superposed on that of point a), to form together therewith the pneumatic connection to the block 116.

Claims: Improved sports footwear comprising a vamp (2) and a sole (3) portion and having at least one insert (4) positioned at least in the heel region of said sole (3), said insert comprising an air-impermeable casing (6) of flexible material and containing elastically deformable means (5,55), characterised in that means (29,36,25,19) are connected to said casing for varying the air pressure within said casing, so as to modify the elastic characteristics of the insert. Sports footwear as claimed in claim 1, characterised in that said means for varying the air pressure within the insert comprise pumping means (29) associated with intake and delivery valve means (25,36) for increasing said pressure, and bleed means (19) for decreasing said pressure. Sports footwear as claimed in claim 2, characterised in that the pumping means and the bleed means are both positioned on the outside of the footwear and are rigid therewith. Sports footwear as claimed in claim 3, characterised in that the pumping means and the bleed means are contained within an elastically deformable cover (45) rigid with the footwear. Sports footwear as claimed in claim 2, characterised in that the pumping means comprise a bellows having two openings (30,35), one containing an intake valve (36) and the other containing a delivery valve (25). Sports footwear as claimed in claim 5, characterised in that the delivery valve is a lip-type valve and is positioned within a block (116) to which the bellows is connected, this block also containing the bleed means downstream of said delivery valve. Sports footwear as claimed in claim 6, characterised in that the bleed means comprise a pusher-type valve. Sports footwear as claimed in claim 1, characterised in that the elastically deformable means are represented by a cellular structure (5), preferably of honeycomb type. Sports footwear as claimed in claim 8, characterised in that the air-impermeable casing of flexible material is formed from at least two parts (6A,6B) each comprising an integral appendix which when joined together form a tube for air passage from and to the insert. Sports footwear as claimed in claim 9, characterised in that said two parts comprise, in coinciding positions, hollow projections (9) which are directed towards the interior of the casing and are connected together at their inner ends. Sports footwear as claimed in claim 10, characterised in that at least one pair of joined-together hollow projections is arranged within a cell (5A) of the cellular structure. Sports footwear as claimed in claim 8, characterised in that the cellular structure is enclosed within, but not connected to, the air-impermeable casing.

Inventors: WONG KING CHEE, WONG, KING CHEE
Applicants: GLOBAL SPORTS TECH INC, GLOBAL SPORTS TECHNOLOGIES INC.
Application year: 1994
Main classification: A43B13
IPC codes: A43B5, A43B7, A43B21, A43B13